Chris Taylor

Yes didn't make a difference.

well the alternator is good, no issues with it at all. So re-fitted it and started the car. Vehicle stuttered for a few seconds, idle was below 300 then it rose to 7000 again. Turned it off and tried it again, same again. It tried to stabilize but quickly went up to max RPM. Checked the codes and it is not showing P0122, which if I remember (don't have the book in front of me) TPS low signal input. Not sure if this is relevant or not.

I have a code scanner, not showing any codes. I am going to pull the alternator today and have it checked by Advance

I will try anything at this point!!

update. All out of ideas, so today went to the local pic a part and got an ECU for $35 to try and eliminate the computer as the issue. Last night the battery was flat so charged it over night. Replaced the ECU, reset the CEL and started the car.....no luck same problem. So replaced the original ECU and TPS, checked the MAF and IAC with the meter as per the Haynes manual. Re-checked the TPS and got good voltages, so looks like I had a bad ground when I checked it the first time. Went to restart the car and the battery did not have enough charge to start the car, only 30 minutes had elapsed since I started it the first time. Is it possible a bad new battery could be causing the problem. My son now tells me that the radio unit is staying on after the ignition is off and the key is out and it wasn't doing this before the battery was replaced. I am now at a total loss, I am going to get this battery replaced and see what happens.

update, daughter managed to get the right TPS from the store. Fitted it but problem still the same along with smoking alternator belt because of the max RPM's. Back to the drawing board. Hoping its not the ECU

didn't check the 5V supply. Meter was grounded well. I will make sure we adjust the voltage to 0.5V as you suggest. May not be until the weekend now as Advance gave my daughter the wrong part and they may not have the right one for a couple of days.

checked the TPS at lunchtime. Minimal voltage throttle open or closed. I have a new TPS coming tomorrow but I am out of town and wont get chance to fit it until Thursday. Hopefully this is the fix. By the way I am always happy to be proven wrong, the only way to learn

Your comment about unburnt fuel is correct, you can smell fuel even after just a few seconds of running. I am going to try and get to the car today and check the TPS voltage as well as linkages etc.

I will take another look at all the vacuum systems, are there any obvious or common culprits. If not I guess it is worth buying a TPS and trying it.

Throttle linkage was my first thought, but it appears to be OK, moving freely etc. Also when I had the airbox off today the flap in the throttle body was closed. That is why I went for the IACV as I think this allows air to bypass the throttle body on a cold start. If I am correct.

cant vouch for the fitting of the battery as I wasn't there when they put it on. The high RPM happens every time the car is started. I tried putting it in gear to see if this dropped the RPM's but that didn't work either. I have checked all the vacuum lines and cannot find any bad areas. Would a dead computer cause any other issues that would point me in that direction?

new to the forum, hoping somebody can shed some light on my issue. 1998 Legacy Outback had it for around 1 year after buying it needing head gaskets, drive shafts, and a couple of other minor issues. Son has been driving this with no problems since I did the rebuild. Last week the battery went bad, got a new one from the local parts store and fitted it. On restarting the engine the idle was rough for a couple of seconds before shooting up to 7000 RPM and staying there. Nothing else was done other than replace the battery. I have cleaned the IACV after checking the forums yesterday. have seen many discussions on rough idle and the need for the ECM to re-learn, but none have mentioned this issue. Vehicle is the 2.5L with 115,000 miles. No other issues in the last 12 months. Help needed....thanks in advance.